Wax-thread sewing-machine.



P. J. WENTWORTH.

WAX THREAD SEWING MACHINE.

APPLICATION FILED DEC. 5, 1912.

2 SHEETS-SHEET l.

P. J. WENTWORTH.

WAX THREAD SEWING MACHINE.

APPLICATION FILED DEC. 5, 1912. 1 1,200,555. Patented 10110,1916.

2 SHEETS-SHEET 2- m: nouns PETERS ca. FHOTOJJIWQ. WASNING row. a. c.

srnrns PATENT anion.

PEARL J. WENTWOBTH, OF MATTAPAN, MASSACHUSETTS, ASSIGNOR T0 UNITED SHOEMACHINERY COMPANY, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

WAX-THREAD SEWING-MACHINE.

Specification of Letters Patent.

Patented Oct. 1o. 191a.

To all whom it may concern:

Be it known that I, PEARL J. VVENTWORTH, a citizen of the United States,residing at Mattapan, in the county of Suffolk and State ofMassachusetts, have invented certain new and useful Improvements in Wax-Thread Sewinglfachines; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to sewing machines and more particularly tomachines for sewing a seam with wax thread.

In the process of sewing a shoe or other piece of work on a wax threadmachine, the operator in removing the work from the machine usuallydraws 05 more or less thread from the supply and cuts off the threadclose to the work. This provides a length of thread extending from thethread handling devices in excess of the amount required to reach to thework and to form the first stitch of the next seam. This excess ofthread is essential in order to enable the first stitch to be formed andtightened in a certain and reliable manner. In a lock stitch machine theneedle thread and in a chain stitch ma chine the single thread must begrasped by the operator or held in some other manner during theformation of the first stitch of the seam. In a lock stitch machine thefree end of the shuttle thread must be long enough to insure thecatching of the shuttle thread my the needle thread when the loop ofneedle thread is drawn down into the work. In any case the first stitchis formed at some distance from the end of the thread and the free endof thread is left projecting from the work at the beginning of the seam.This free end of thread is usually cut off by the operator by means of ahand knife when the seam is finished and this operation necessarilyconsumes considerable time. When light colored stock is being sewn thefree end of the thread, if it is not cut ofi until the completion of theseam, is liable to soil the workby contact therewith during the sewingoperation.

The primary objects of the present lnvention are to provide a wax threadsewing machine with means whereby the free end of the thread at thebeginning of the seam is severed close to the work in a certain andreliable manner without waste of time and with very little care, skillor effort on the part of the operator.

WVith these objects in view the invention comprises various novel andadvantageous features clearly set forth in the following description andpointed out in the claims appended thereto.

In the accompanying drawings illustrating the invention in its preferredform, Fig ure 1 is a front elevation of a portion of a sewing machineembodying the invention; Fig. 2 is a plan view of a portion of themechanism illustrated in Fig. 1, showing particularly the presser foot,the work sup port, and the parts adjacent thereto; Fig. 3 is a plan viewof the work support detached from the machine; and Fig. el is a similarview of the presser foot.

The sewing machine illustrated in the drawings is a lock stitch, waxthread machine for sewing the outsoles to the uppers of boots and shoes,and in general the parts of the machine are the same in constructionarrangement and mode of operation as the corresponding parts in themachine illustrated in the patent to French and Meyer, No. 173,870,dated April 26, 1892. The stitch forming devices of the machine comprisea curved hook needle indicated at 1, a looper 2 for laying the lowerthread indicated at f about the needle, a thread finger 5, and a rotaryshuttle 6 containing the upper or look ing thread indicated at 7. Thework is supported by a work support 8 and a presser foot 9 cooperateswith the work support to holdthe work in position during the formationof the stitches. The work is fed by the lateral movement of a curved awl10 while the awl is in engagement with the work. The awl is secured toan awl segment 11 which is mounted to oscillate upon the upper end of anupright 12 secured to the feed slide 13. The feed slide is reciprocatedto feed the work by means of an oscillatory lever 14, the forwardlyextending arm of which is provided with an arc shaped groove to receivea roll 15 mounted on the feed changing lever 16 pivoted to the feedslide. The lever 1a is provided with a roll 17 which engages a camgroove 18 in a cam disk 19 secured to the cam shaft of the machine, notshown.

When the seam about the sole of the shoe has been completed, theoperator lifts the presser foot from the machine and removes the workfrom between the presser foot and the work support. As the operatorremoves the work from the machine he draws off more or less of both theupper and lower threads from the respective sources of thread supply,and cuts both threads close to the work. This provides lengths of bothupper and lower threads in excess of the amount required to reach to thework and to form the first stitch. The excess in the length of the upperthread insures the catching of the upper thread in the loop of the lowerthread as the lower thread after passing about the shuttle is pulleddown into the work by the takeup. The excess in the length of the lowerthread enables the end of the lower thread to be held during theformation of the first stitch. The first stitch is formed at. somedistance from the free ends of the threads and in the present invention,provision is made for cutting off the projecting free ends of both theupper and lower threads close to the work. To this end cutting devicesare provided for cutting both the upper and lower threads, and in theillustrated embodiment of the invention these cutting devices arearranged so that the threads when held at a point relatively remote fromthe sewing point in a manner hereinafter explained are carried againstthe cutting edges of the cutting devices to sever the thread by the feedmove ment of the shoe during the sewing opera tion. The cutting devicefor the upper thread consists of a knife indicated at 20 secured to orformed integral with the presser foot. The knife 20 is made in the formof a hook which extends in advance of the sewing point and across theline of the seam, as shown in Fig. 2. The cutting device for the lowerthread consists of a hook shaped knife 21 mounted upon the work supportin advance of the sewing point. The work support is cut away in front toprovide a recess in advance of the knife to receive the thread as shownin Fig. 3. In order to enable the knife to yield rearwardly when itshooked end comes in contact with the edge of the toe cap or any otherabrupt surface on'the shoe, so that it will not injure the shoe, theknife is formed on a dovetail slide 22 which is mounted in a dove-tailgroove in the work support. The knife slide is yieldingly pressedforward by means of a spring 24 which engages its rear edge. Theundercut portion ofthe right-hand side of the groove in the work support(Fig. 3) is terminated short of the forward portion of the foot so as toform a stop 23 to engage the knife slide and limit the forward movementthereof.

Before the work is inserted in the machine the end of the lower threadwhich extends up through the slot in the work support is grasped by theoperator and drawn along the front of the work support until it dropsinto the recess'in front of the knife 21. At the beginning of the sewingof a scam the shoe is presented to the machine with the sole and weltbetween the presser foot and work support, and the operator grasps theend of the thread 7 in his left hand while still holding the shoe, andholds this thread fairly taut in advance of and slightly back of thesewing point. The lower thread, after having been inserted in front ofthe thread cutting knife 21, as stated above, may be held in the lefthand of the operator, or the end of this thread may be held in anysuitable gripping device attached to the machine. In the illustratedembodiment of the invention the end of the thread is held by a grippingdevice consisting of a spring plate 26 secured to the shank of the worksupport, the thread being gripped between the spring plate and theadjacent face of the work support shank. The lower thread may beinserted beneath the spring plate 26 at the time when it is drawn infront of the cutting knife 21. Upon starting the machine the needleadvances through the work, receives the lower thread from the looper,draws the loop of lower thread through the work, which loop is thencaught by the hook of and passed about the shuttle, after which thetakeup acts'to tighten the stitch, drawing the lock between the upperand lower threads down into the work. During this operation the upperthread is drawn down in front of the upper thread cutting hook or knife20, as shown in Figs. 1 and 2. After the first stitch is formed, boththe upper and lower threads lie in front of the hook shaped cuttingknives 20 and 21 respectively, and when the work is fed both threads aredrawn toward the cutting edges of the knives. The upper thread 7 beingheld in the hand of the operator is held taut and carried along with theshoe as the shoe is fed. The lower thread, whether held in the hand ofthe operator or beneath the spring plate 26, is kept taut by the actionof the takeup. hen the work has been fed a suflicient amount, the pullof the upper and lower threads against the edges of the cutting kniveswill cause the severing of the threads close to the work. In a machineconstructed as illustrated in the draw ings, the threads will be severedduring the feed movement of the work subsequent to the formation of thesecond stitch of the seam.

By means of the above described cutting devices the projecting free endsof the threads are cut close to the work at the beginning of the seam ina reliable and eflicient manner without loss of time, and with verylittle skill or effort on the part of the operator. Since the free endof the thread is severed at the beginning of the sewing operation thesoiling of the work by the contact of the free end of the threadtherewith during the sewing operation is obviated.

Having explained the nature and object of the invention, and havingdescribed a ma-' chine in which the invention may be embodied, what isclaimed is 1. A sewing machine, having in combination, stitch formingdevices, constructed and arranged to form a linearly extending series ofstitches, work feeding means, and a thread cutting device arranged tosever close to the work during the first part of the seam formation andafter one or more stitches have been set in the work, the free end ofthe thread projecting from the work at the beginning of the seam.

2. A sewing machine, having in combination, stitch forming devicesconstructed and arranged to form a two thread seam and thread cuttingdevices arranged to sever close to the work during the first part of theseam formation the free ends of both the upper and under threadsprojecting from the work at the beginning of the seam.

3. A sewing machine, having in combination, stitch forming devicesconstructed and arranged to form a linearly extending series ofstitches, work feeding means, a thread gripping device for gripping andholding the free end of the thread during the first part of the seamformation and a thread severing device constructed and arranged to severbetween the gripping device and the work during the first part of theseam formation and after one or more stitches have been set in the work,the free end of the thread projecting from the work at the beginning ofthe seam.

4. A sewing machine, having in combination, stitch forming devices, Workfeeding means, and a thread cutting knife mounted on the thread supplyside of the work and close to the sewing point in position for the freeend of the thread projecting from the work at the beginning of the seamto be drawn against the knife by the feed movement of the work duringthe first part of the seam formation for severing close to the work thefree end of the thread.

5. A sewing machine, having, in combination, stitch forming devices,feeding means, means for supporting the work and a thread cutting knifemounted on the work supporting means for yielding movement in adirection away from the work when engaged by the work.

6. A sewing machine, having in combination, stitch forming devicesconstructed and arranged to form a two thread seam, work feeding means,a work support, a presser foot and two thread cutting knives mountedrespectively on the work support and presser foot and arranged to severclose to the work during the first part of the seam formation, the freeends of the upper and under threads projecting from the work at thebeginning of the seam.

7 A sewing machine, having in combination, stitch forming devicesconstructed and arranged to form a two thread seam, work feeding means,a work support, a presser foot, two thread cutting knives mountedrespectively on the work support and presser foot and arranged to severclose to the work during the first part of the seam formation the freeends of both the upper and under threads pro ecting from the work at thebeginning of the seam and a thread gripping device for gripping one ofthe threads while the thread is severed between the gripping device andthe work by one of the knives.

PEARL J. WENTWORTH.

Witnesses:

OHA NOEY M. SINGERBEAUX, BURTON W. CARY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. O.

